Augmented reality system using structured light

ABSTRACT

An augmented reality system having a light source and a camera. The light source projects a pattern of light onto a scene, the pattern being periodic. The camera captures an image of the scene including the projected pattern. A projector pixel of the projected pattern corresponding to an image pixel of the captured image is determined. A disparity of each correspondence is determined, the disparity being an amount that corresponding pixels are displaced between the projected pattern and the captured image. A three-dimensional computer model of the scene is generated based on the disparity. A virtual object in the scene is rendered based on the three-dimensional computer model.

TECHNICAL FIELD

Embodiments of the present disclosure relate generally to mobilecomputing technology and, more particularly, but not by way oflimitation, to systems for generating and presenting augmented realitymedia content.

BACKGROUND

Augmented reality refers to using computer generated enhancements to addnew information into images in a real-time or near real-time fashion.For example, video images of a wall output on a display of a device maybe enhanced with display details that are not present on the wall, butthat are generated to appear as if they are on the wall by an augmentedreality system. Such systems require a complex mix of image captureinformation that is integrated and matched with the augmented realityinformation that is to be added to a captured scene in a way thatattempts to seamlessly present a final image from a perspectivedetermined by the image capture device.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Various ones of the appended drawings merely illustrate exampleembodiments of the present disclosure and should not be considered aslimiting its scope.

FIG. 1A is a block diagram for explaining an example messaging systemfor exchanging data (e.g., messages and associated content) over anetwork in accordance with some embodiments, wherein the messagingsystem includes an augmented reality system.

FIG. 1B illustrates one example for explaining a client device accordingto some embodiments.

FIG. 2 is block diagram for explaining further details regarding amessaging system, according to example embodiments.

FIG. 3 is a schematic diagram for explaining data which may be stored inthe database of the messaging server system, according to exampleembodiments.

FIG. 4 is a schematic diagram for explaining a structure of a message,according to some embodiments, generated by a messaging clientapplication for communication.

FIG. 5 is a schematic diagram for explaining an example access-limitingprocess, in terms of which access to content (e.g., an ephemeralmessage, and associated multimedia payload of data) or a contentcollection (e.g., an ephemeral message story) may be time-limited (e.g.,made ephemeral) in accordance with some embodiments.

FIG. 6 is a block diagram for explaining various modules of an augmentedreality system, according to example embodiments.

FIG. 7 is a schematic diagram for explaining an example augmentedreality system according to some example embodiments.

FIG. 8 is a graphical representation for explaining example projectedpatterns according to some example embodiments.

FIG. 9 is a schematic diagram for explaining window size according tosome example embodiments.

FIG. 10 is a flow chart for explaining a method of projecting structuredlight to recover three-dimensional data according to some exampleembodiments.

FIG. 11 is a block diagram for explaining a representative softwarearchitecture, which may be used in conjunction with various hardwarearchitectures herein described and used to implement variousembodiments.

FIG. 12 is a block diagram for explaining components of a machine,according to some example embodiments, able to read instructions from amachine-readable medium (e.g., a machine-readable storage medium) andperform any one or more of the methodologies discussed herein.

DETAILED DESCRIPTION

Embodiments of the present disclosure relate generally to mobilecomputing technology and, more particularly, but not by way oflimitation, to systems for generating and presenting augmented realitymedia content. An Augmented Reality (AR) system as described herein maybe or include any instrumentality or aggregate of instrumentalitiesoperable to compute, process, store, display, generate, communicate, orapply various forms of data for generating and presenting interfaces forthe display of AR media content.

In accordance with various embodiments described herein, an augmentedreality (AR) system is provided on a mobile platform (e.g., a mobilephone, a tablet computer, etc.) In order for the AR system to place avirtual object in a scene in a geometrically accurate manner, it isdesirable to obtain accurate information about the geometry of the scene(e.g., depth information). In one aspect described herein, suchinformation is obtained using structured light.

In some embodiments, the AR system includes a light source and a camera.Generally, light source projects of a pattern of light onto a scene. Thecamera captures an image of the scene including the projected pattern. Aprojector pixel of the projected pattern is determined that correspondsto an image pixel of the captured image. A disparity of eachcorrespondence is determined, the disparity being an amount thatcorresponding pixels are displaced between the projected pattern and thecaptured image. A three-dimensional computer model of the scene isgenerated based on the disparity and a virtual object is rendered in thescene based on the computer model.

In some embodiments, a distance between a location of the light sourceand a location of the camera is from 5 mm to 10 mm. In some embodiments,a distance between a location of the light source and a location of thecamera is 20 mm.

In some embodiments, a size of a window for determining the disparity isgreater than a greatest disparity that is estimated based on a targetdepth range of the scene, the greatest disparity being the largestamount that corresponding pixels are displaced between the projectedpattern and the captured image.

In some embodiments, the projected pattern is periodic. In someembodiments, the period of the pattern is equal to the window size. Insome embodiments, the projected pattern is a triangular pattern.

In some embodiments, the AR system also includes a mask havingtransparent areas and opaque areas, wherein the mask modulates anintensity of light from the light source. In some embodiments, the ARsystem also includes a lens to project the pattern onto the scene.

In some embodiments, the light source is a light emitting diode (LED).In some embodiments, the light source is a laser.

In some embodiments, the computer model comprises a depth map. In someembodiments, the computer model comprises a video rate depth map.

In some embodiments, an image of the scene without the projected patternis captured. A difference is determined between the image capturedincluding the projected pattern and the image captured without theprojected pattern. In some aspects, causing the camera to capture theimage of the scene including the projected pattern, causing the camerato capture the image of the scene without the projected pattern, anddetermining the difference are performed at a frame rate equal to aframe rate of the camera to generate: (i) depth maps at half the framerate of the camera and (ii) a video at half the frame rate of thecamera, the video being free of the projected pattern.

By virtue of the embodiments described above, it is possible to providean AR system that obtains depth information by capturing only one or twoimages, such that it is robust to motion artifacts (e.g., due to eithermotion of the mobile device or motion of the scene). In addition, it ispossible to provide an AR system that allows for simple decoding, suchthat computational resources are not heavily burdened. Also, it ispossible to provide an AR system having a small baseline (e.g., smallfootprint of the mobile device itself).

FIG. 1A is a block diagram showing an example messaging system 100 forexchanging data (e.g., messages and associated content) over a network.The messaging system 100 includes multiple client devices 102, each ofwhich hosts a number of applications including a messaging clientapplication 104. Each messaging client application 104 iscommunicatively coupled to other instances of the messaging clientapplication 104 and a messaging server system 108 via a network 106(e.g., the Internet).

Accordingly, each messaging client application 104 is able tocommunicate and exchange data with another messaging client application104 and with the messaging server system 108 via the network 106. Thedata exchanged between messaging client applications 104, and between amessaging client application 104 and the messaging server system 108,includes functions (e.g., commands to invoke functions) as well aspayload data (e.g., text, audio, video or other multimedia data).

The messaging server system 108 provides server-side functionality viathe network 106 to a particular messaging client application 104. Whilecertain functions of the messaging system 100 are described herein asbeing performed by either a messaging client application 104 or by themessaging server system 108, it will be appreciated that the location ofcertain functionality either within the messaging client application 104or the messaging server system 108 is a design choice. For example, itmay be technically preferable to initially deploy certain technology andfunctionality within the messaging server system 108, but to latermigrate this technology and functionality to the messaging clientapplication 104 where a client device 102 has a sufficient processingcapacity.

The messaging server system 108 supports various services and operationsthat are provided to the messaging client application 104. Suchoperations include transmitting data to, receiving data from, andprocessing data generated by the messaging client application 104. Insome embodiments, this data includes, message content, client deviceinformation, geolocation information, media annotation and overlays,message content persistence conditions, social network information, andlive event information, as examples. In other embodiments, other data isused. Data exchanges within the messaging system 100 are invoked andcontrolled through functions available via user interfaces (UIs) of themessaging client application 104.

Turning now specifically to the messaging server system 108, anApplication Program Interface (API) server 110 is coupled to, andprovides a programmatic interface to, an application server 112. Theapplication server 112 is communicatively coupled to a database server118, which facilitates access to a database 120 in which is stored dataassociated with messages processed by the application server 112.

Dealing specifically with the Application Program Interface (API) server110, this server receives and transmits message data (e.g., commands andmessage payloads) between the client device 102 and the applicationserver 112. Specifically, the Application Program Interface (API) server110 provides a set of interfaces (e.g., routines and protocols) that canbe called or queried by the messaging client application 104 in order toinvoke functionality of the application server 112. The ApplicationProgram Interface (API) server 110 exposes various functions supportedby the application server 112, including account registration, loginfunctionality, the sending of messages, via the application server 112,from a particular messaging client application 104 to another messagingclient application 104, the sending of media files (e.g., images orvideo) from a messaging client application 104 to the messaging serverapplication 114, and for possible access by another messaging clientapplication 104, the setting of a collection of media data (e.g.,story), the retrieval of a list of friends of a user of a client device102, the retrieval of such collections, the retrieval of messages andcontent, the adding and deletion of friends to a social graph, thelocation of friends within a social graph, opening and application event(e.g., relating to the messaging client application 104).

The application server 112 hosts a number of applications andsubsystems, including a messaging server application 114, an imageprocessing system 116, a social network system 122, and an augmentedreality (AR) system 124. The messaging server application 114 implementsa number of message processing technologies and functions, particularlyrelated to the aggregation and other processing of content (e.g.,textual and multimedia content) included in messages received frommultiple instances of the messaging client application 104. As will bedescribed in further detail, the text and media content from multiplesources may be aggregated into collections of content (e.g., calledstories or galleries). These collections are then made available, by themessaging server application 114, to the messaging client application104. Other processor and memory intensive processing of data may also beperformed server-side by the messaging server application 114, in viewof the hardware requirements for such processing.

The application server 112 also includes an image processing system 116that is dedicated to performing various image processing operations,typically with respect to images or video received within the payload ofa message at the messaging server application 114.

The social network system 122 supports various social networkingfunctions services, and makes these functions and services available tothe messaging server application 114. To this end, the social networksystem 122 maintains and accesses an entity graph 304 within thedatabase 120. Examples of functions and services supported by the socialnetwork system 122 include the identification of other users of themessaging system 100 with which a particular user has relationships oris “following,” and also the identification of other entities andinterests of a particular user.

The application server 112 is communicatively coupled to a databaseserver 118, which facilitates access to a database 120 in which isstored data associated with messages processed by the messaging serverapplication 114.

FIG. 1B illustrates one example for explaining a client device 102 thatis be used for an augmented reality system according to someembodiments. As shown in FIG. 1B, the client device 102 includes a lightsource 140 and a camera 130 a. Generally, light source 140 projects apattern of light onto a scene. The camera 130 captures an image of thescene including the projected pattern.

Light source 140 and camera 130 have a fixed geometrical relationship toeach other. In some embodiments, a distance 170 between a location ofthe light source 140 and a location of the camera 130 is in a rangebetween 5 mm to 10 mm. In some embodiments, the distance 170 between alocation of the light source and a location of the camera is 20 mm.

In some embodiments, a device display area 150 presents augmentedreality images as described herein. Inputs and adjustments to any systemoperation described herein may be performed using touch screen inputswithin device display area 150 by a user. Although the embodiment ofFIG. 1B illustrates display area 150 on the same surface as camera 130and light source 140, in other embodiments, the display area 150 islocated on the opposite surface from camera 130 and light source 140.

FIG. 1B illustrates an example mobile device 102 executing a mobileoperating system (e.g., IOS™, ANDROID™, WINDOWS® Phone, or other mobileoperating systems), consistent with some embodiments. In one embodiment,the mobile device 102 includes a touch screen operable to receivetactile data from a user. For instance, the user may physically touchthe mobile device 102, and in response to the touch, the mobile device102 may determine tactile data such as touch location, touch force, orgesture motion. In various example embodiments, the mobile device 102displays a home screen (e.g., Springboard on IOS™) operable to launchapplications or otherwise manage various aspects of the mobile device102. In some example embodiments, the home screen provides statusinformation such as battery life, connectivity, or other hardwarestatuses. The user can activate user interface elements by touching anarea occupied by a respective user interface element. In this manner,the user interacts with the applications of the mobile device 102. Forexample, touching the area occupied by a particular icon included in thehome screen causes launching of an application corresponding to theparticular icon.

Many varieties of applications (also referred to as “apps”) can beexecuted on the mobile device 102, such as native applications (e.g.,applications programmed in Objective-C, Swift, or another suitablelanguage running on IOS™, or applications programmed in Java running onANDROID™), mobile web applications (e.g., applications written inHypertext Markup Language-5 (HTML5)), or hybrid applications (e.g., anative shell application that launches an HTML5 session). For example,the mobile device 102 includes a messaging app, an audio recording app,a camera app, a book reader app, a media app, a fitness app, a filemanagement app, a location app, a browser app, a settings app, acontacts app, a telephone call app, or other apps (e.g., gaming apps,social networking apps, biometric monitoring apps). In another example,the mobile device 102 includes a social messaging app, consistent withsome embodiments, that allows users to exchange ephemeral messages thatinclude media content. In this example, the social messaging app canincorporate aspects of embodiments described herein.

FIG. 2 is block diagram illustrating further details regarding themessaging system 100, according to example embodiments. Specifically,the messaging system 100 is shown to comprise the messaging clientapplication 104 and the application server 112, which in turn embody anumber of some subsystems, namely an ephemeral timer system 202, acollection management system 204 and an annotation system 206.

The ephemeral timer system 202 is responsible for enforcing thetemporary access to content permitted by the messaging clientapplication 104 and the messaging server application 114. To this end,the ephemeral timer system 202 incorporates a number of timers that,based on duration and display parameters associated with a message,collection of messages (e.g., a SNAPCHAT story), or graphical element,selectively display and enable access to messages and associated contentvia the messaging client application 104. Further details regarding theoperation of the ephemeral timer system 202 are provided below.

The collection management system 204 is responsible for managingcollections of media (e.g., collections of text, image video and audiodata). In some examples, a collection of content (e.g., messages,including images, video, text and audio) may be organized into an “eventgallery” or an “event story.” Such a collection may be made availablefor a specified time period, such as the duration of an event to whichthe content relates. For example, content relating to a music concertmay be made available as a “story” for the duration of that musicconcert. The collection management system 204 may also be responsiblefor publishing an icon that provides notification of the existence of aparticular collection to the user interface of the messaging clientapplication 104.

The collection management system 204 furthermore includes a curationinterface 208 that allows a collection manager to manage and curate aparticular collection of content. For example, the curation interface208 enables an event organizer to curate a collection of contentrelating to a specific event (e.g., delete inappropriate content orredundant messages). Additionally, the collection management system 204employs machine vision (or image recognition technology) and contentrules to automatically curate a content collection. In certainembodiments, compensation may be paid to a user for inclusion of usergenerated content into a collection. In such cases, the curationinterface 208 operates to automatically make payments to such users forthe use of their content.

The annotation system 206 provides various functions that enable a userto annotate or otherwise modify or edit media content associated with amessage. For example, the annotation system 206 provides functionsrelated to the generation and publishing of media overlays for messagesprocessed by the messaging system 100. The annotation system 206operatively supplies a media overlay (e.g., a SNAPCHAT filter) to themessaging client application 104 based on a geolocation of the clientdevice 102. In another example, the annotation system 206 operativelysupplies a media overlay to the messaging client application 104 basedon other information, such as, social network information of the user ofthe client device 102. A media overlay may include audio and visualcontent and visual effects. Examples of audio and visual content includepictures, texts, logos, animations, and sound effects. An example of avisual effect includes color overlaying. The audio and visual content orthe visual effects can be applied to a media content item (e.g., aphoto) at the client device 102. For example, the media overlayincluding text that can be overlaid on top of a photograph generatedtaken by the client device 102. In another example, the media overlayincludes an identification of a location overlay (e.g., Venice beach), aname of a live event, or a name of a merchant overlay (e.g., BeachCoffee House). In another example, the annotation system 206 uses thegeolocation of the client device 102 to identify a media overlay thatincludes the name of a merchant at the geolocation of the client device102. The media overlay may include other indicia associated with themerchant. The media overlays may be stored in the database 120 andaccessed through the database server 118.

In one example embodiment, the annotation system 206 provides auser-based publication platform that enables users to select ageolocation on a map, and upload content associated with the selectedgeolocation. The user may also specify circumstances under which aparticular media overlay should be offered to other users. Theannotation system 206 generates a media overlay that includes theuploaded content and associates the uploaded content with the selectedgeolocation.

In another example embodiment, the annotation system 206 provides amerchant-based publication platform that enables merchants to select aparticular media overlay associated with a geolocation via a biddingprocess. For example, the annotation system 206 associates the mediaoverlay of a highest bidding merchant with a corresponding geolocationfor a predefined amount of time

FIG. 3 is a schematic diagram 300 illustrating data 300 which may bestored in the database 120 of the messaging server system 108, accordingto certain example embodiments. While the content of the database 120 isshown to comprise a number of tables, it will be appreciated that thedata could be stored in other types of data structures (e.g., as anobject-oriented database).

The database 120 includes message data stored within a message table314. The entity table 302 stores entity data, including an entity graph304. Entities for which records are maintained within the entity table302 may include individuals, corporate entities, organizations, objects,places, events etc. Regardless of type, any entity regarding which themessaging server system 108 stores data may be a recognized entity. Eachentity is provided with a unique identifier, as well as an entity typeidentifier (not shown).

The entity graph 304 furthermore stores information regardingrelationships and associations between entities. Such relationships maybe social, professional (e.g., work at a common corporation ororganization) interested-based or activity-based, merely for example.

The database 120 also stores annotation data, in the example form offilters, in an annotation table 312. Filters for which data is storedwithin the annotation table 312 are associated with and applied tovideos (for which data is stored in a video table 310) and/or images(for which data is stored in an image table 308). Filters, in oneexample, are overlays that are displayed as overlaid on an image orvideo during presentation to a recipient user. Filters may be of variestypes, including a user-selected filters from a gallery of filterspresented to a sending user by the messaging client application 104 whenthe sending user is composing a message. Other types of filers includegeolocation filters (also known as geo-filters) which may be presentedto a sending user based on geographic location. For example, geolocationfilters specific to a neighborhood or special location may be presentedwithin a user interface by the messaging client application 104, basedon geolocation information determined by a GPS unit of the client device102. Another type of filer is a data filer, which may be selectivelypresented to a sending user by the messaging client application 104,based on other inputs or information gathered by the client device 102during the message creation process. Example of data filters includecurrent temperature at a specific location, a current speed at which asending user is traveling, battery life for a client device 102 or thecurrent time.

Other annotation data that may be stored within the image table 308 isso-called “lens” data. A “lens” may be a real-time special effect andsound that may be added to an image or a video.

As mentioned above, the video table 310 stores video data which, in oneembodiment, is associated with messages for which records are maintainedwithin the message table 314. Similarly, the image table 308 storesimage data associated with messages for which message data is stored inthe entity table 302. The entity table 302 may associate variousannotations from the annotation table 312 with various images and videosstored in the image table 308 and the video table 310.

A story table 306 stores data regarding collections of messages andassociated image, video or audio data, which are compiled into acollection (e.g., a SNAPCHAT story or a gallery). The creation of aparticular collection may be initiated by a particular user (e.g., eachuser for which a record is maintained in the entity table 302) A usermay create a “personal story” in the form of a collection of contentthat has been created and sent/broadcast by that user. To this end, theuser interface of the messaging client application 104 may include anicon that is user selectable to enable a sending user to add specificcontent to his or her personal story.

A collection may also constitute a “live story,” which is a collectionof content from multiple users that is created manually, automaticallyor using a combination of manual and automatic techniques. For example,a “live story” may constitute a curated stream of user-submitted contentfrom varies locations and events. Users, whose client devices havelocation services enabled and are at a common location event at aparticular time may, for example, be presented with an option, via auser interface of the messaging client application 104, to contributecontent to a particular live story. The live story may be identified tothe user by the messaging client application 104, based on his or herlocation. The end result is a “live story” told from a communityperspective.

A further type of content collection is known as a “location story”,which enables a user whose client device 102 is located within aspecific geographic location (e.g., on a college or university campus)to contribute to a particular collection. In some embodiments, acontribution to a location story may require a second degree ofauthentication to verify that the end user belongs to a specificorganization or other entity (e.g., is a student on the universitycampus).

FIG. 4 is a schematic diagram illustrating a structure of a message 400,according to some in some embodiments, generated by a messaging clientapplication 104 for communication to a further messaging clientapplication 104 or the messaging server application 114. The content ofa particular message 400 is used to populate the message table 314stored within the database 120, accessible by the messaging serverapplication 114. Similarly, the content of a message 400 is stored inmemory as “in-transit” or “in-flight” data of the client device 102 orthe application server 112. The message 400 is shown to include thefollowing components:

-   -   A message identifier 402: a unique identifier that identifies        the message 400.    -   A message text payload 404: text, to be generated by a user via        a user interface of the client device 102 and that is included        in the message 400.    -   A message image payload 406: image data, captured by a camera        component of a client device 102 or retrieved from memory of a        client device 102, and that is included in the message 400.    -   A message video payload 408: video data, captured by a camera        component or retrieved from a memory component of the client        device 102 and that is included in the message 400.    -   A message audio payload 410: audio data, captured by a        microphone or retrieved from the memory component of the client        device 102, and that is included in the message 400.    -   A message annotations 412: annotation data (e.g., filters,        stickers or other enhancements) that represents annotations to        be applied to message image payload 406, message video payload        408, or message audio payload 410 of the message 400.    -   A message duration parameter 414: parameter value indicating, in        seconds, the amount of time for which content of the message        (e.g., the message image payload 406, message video payload 408,        message audio payload 410) is to be presented or made accessible        to a user via the messaging client application 104.    -   A message geolocation parameter 416: geolocation data (e.g.,        latitudinal and longitudinal coordinates) associated with the        content payload of the message. Multiple message geolocation        parameter 416 values may be included in the payload, each of        these parameter values being associated with respect to content        items included in the content (e.g., a specific image into        within the message image payload 406, or a specific video in the        message video payload 408).    -   A message story identifier 418: identifier values identifying        one or more content collections (e.g., “stories”) with which a        particular content item in the message image payload 406 of the        message 400 is associated. For example, multiple images within        the message image payload 406 may each be associated with        multiple content collections using identifier values.    -   A message tag 420: each message 400 may be tagged with multiple        tags, each of which is indicative of the subject matter of        content included in the message payload. For example, where a        particular image included in the message image payload 406        depicts an animal (e.g., a lion), a tag value may be included        within the message tag 420 that is indicative of the relevant        animal. Tag values may be generated manually, based on user        input, or may be automatically generated using, for example,        image recognition.    -   A message sender identifier 422: an identifier (e.g., a        messaging system identifier, email address or device identifier)        indicative of a user of the client device 102 on which the        message 400 was generated and from which the message 400 was        sent    -   A message receiver identifier 424: an identifier (e.g., a        messaging system identifier, email address or device identifier)        indicative of a user of the client device 102 to which the        message 400 is addressed.

The contents (e.g. values) of the various components of message 400 maybe pointers to locations in tables within which content data values arestored. For example, an image value in the message image payload 406 maybe a pointer to (or address of) a location within an image table 308.Similarly, values within the message video payload 408 may point to datastored within a video table 310, values stored within the messageannotations 412 may point to data stored in an annotation table 312,values stored within the message story identifier 418 may point to datastored in a story table 306, and values stored within the message senderidentifier 422 and the message receiver identifier 424 may point to userrecords stored within an entity table 302.

FIG. 5 is a schematic diagram illustrating an access-limiting process500, in terms of which access to content (e.g., an ephemeral message502, and associated multimedia payload of data) or a content collection(e.g., an ephemeral message story 504) may be time-limited (e.g., madeephemeral).

An ephemeral message 502 is shown to be associated with a messageduration parameter 506, the value of which determines an amount of timethat the ephemeral message 502 will be displayed to a receiving user ofthe ephemeral message 502 by the messaging client application 104. Inone embodiment, where the messaging client application 104 is a SNAPCHATapplication client, an ephemeral message 502 is viewable by a receivinguser for up to a maximum of 10 seconds, depending on the amount of timethat the sending user specifies using the message duration parameter506.

The message duration parameter 506 and the message receiver identifier424 are shown to be inputs to a message timer 512, which is responsiblefor determining the amount of time that the ephemeral message 502 isshown to a particular receiving user identified by the message receiveridentifier 424. In particular, the ephemeral message 502 will only beshown to the relevant receiving user for a time period determined by thevalue of the message duration parameter 506. The message timer 512 isshown to provide output to a more generalized ephemeral timer system202, which is responsible for the overall timing of display of content(e.g., an ephemeral message 502) to a receiving user.

The ephemeral message 502 is shown in FIG. 5 to be included within anephemeral message story 504 (e.g., a personal SNAPCHAT story, or anevent story). The ephemeral message story 504 has an associated storyduration parameter 508, a value of which determines a time-duration forwhich the ephemeral message story 504 is presented and accessible tousers of the messaging system 100. The story duration parameter 508, forexample, may be the duration of a music concert, where the ephemeralmessage story 504 is a collection of content pertaining to that concert.Alternatively, a user (either the owning user or a curator user) mayspecify the value for the story duration parameter 508 when performingthe setup and creation of the ephemeral message story 504.

Additionally, each ephemeral message 502 within the ephemeral messagestory 504 has an associated story participation parameter 510, a valueof which determines the duration of time for which the ephemeral message502 will be accessible within the context of the ephemeral message story504. Accordingly, a particular ephemeral message story 504 may “expire”and become inaccessible within the context of the ephemeral messagestory 504, prior to the ephemeral message story 504 itself expiring interms of the story duration parameter 508. The story duration parameter508, story participation parameter 510, and message receiver identifier424 each provide input to a story timer 514, which operationallydetermines, firstly, whether a particular ephemeral message 502 of theephemeral message story 504 will be displayed to a particular receivinguser and, if so, for how long. Note that the ephemeral message story 504is also aware of the identity of the particular receiving user as aresult of the message receiver identifier 424.

Accordingly, the story timer 514 operationally controls the overalllifespan of an associated ephemeral message story 504, as well as anindividual ephemeral message 502 included in the ephemeral message story504. In one embodiment, each and every ephemeral message 502 within theephemeral message story 504 remains viewable and accessible for atime-period specified by the story duration parameter 508. In a furtherembodiment, a certain ephemeral message 502 may expire, within thecontext of ephemeral message story 504, based on a story participationparameter 510. Note that a message duration parameter 506 may stilldetermine the duration of time for which a particular ephemeral message502 is displayed to a receiving user, even within the context of theephemeral message story 504. Accordingly, the message duration parameter506 determines the duration of time that a particular ephemeral message502 is displayed to a receiving user, regardless of whether thereceiving user is viewing that ephemeral message 502 inside or outsidethe context of an ephemeral message story 504.

The ephemeral timer system 202 may furthermore operationally remove aparticular ephemeral message 502 from the ephemeral message story 504based on a determination that it has exceeded an associated storyparticipation parameter 510. For example, when a sending user hasestablished a story participation parameter 510 of 24 hours fromposting, the ephemeral timer system 202 will remove the relevantephemeral message 502 from the ephemeral message story 504 after thespecified 24 hours. The ephemeral timer system 202 also operates toremove an ephemeral message story 504 either when the storyparticipation parameter 510 for each and every ephemeral message 502within the ephemeral message story 504 has expired, or when theephemeral message story 504 itself has expired in terms of the storyduration parameter 508.

In certain use cases, a creator of a particular ephemeral message story504 may specify an indefinite story duration parameter 508. In thiscase, the expiration of the story participation parameter 510 for thelast remaining ephemeral message 502 within the ephemeral message story504 will determine when the ephemeral message story 504 itself expires.In this case, a new ephemeral message 502, added to the ephemeralmessage story 504, with a new story participation parameter 510,effectively extends the life of an ephemeral message story 504 to equalthe value of the story participation parameter 510.

Responsive to the ephemeral timer system 202 determining that anephemeral message story 504 has expired (e.g., is no longer accessible),the ephemeral timer system 202 communicates with the messaging system100 (and, for example, specifically the messaging client application 104to cause an indicium (e.g., an icon) associated with the relevantephemeral message story 504 to no longer be displayed within a userinterface of the messaging client application 104. Similarly, when theephemeral timer system 202 determines that the message durationparameter 506 for a particular ephemeral message 502 has expired, theephemeral timer system 202 causes the messaging client application 104to no longer display an indicium (e.g., an icon or textualidentification) associated with the ephemeral message 502.

FIG. 6 is a block diagram illustrating example components of the ARsystem 124 according to some embodiments. The augmented reality system160 is shown to include an image-based location system 161, acommunication module 210, a presentation module 220, a configurationmodule 230, an alignment module 240, a virtual item module 250, ananalysis module 260, and a map positioning system 270. All, or some, ofthe modules 210-270 communicate with each other, for example, via anetwork coupling, shared memory, and the like. Each module of themodules of augmented reality system 160 can be implemented as a singlemodule, combined into other modules, or further subdivided into multiplemodules. Other modules not pertinent to example embodiments can also beincluded, but are not shown.

The communication module 210 provides various communicationfunctionality. For example, the communication module 210 receives,accesses, or otherwise obtains image data of an image from a userdevice. In a specific example, the communication module 210 receivessubstantially real-time image data from a camera sensor of a smart phone(e.g., a single frame of image data or a continuous stream of framescaptured by a camera sensor of the smart phone). The communicationmodule 210 exchanges network communications with the database servers132, the client devices 110, and the third party servers 120. Theinformation retrieved by the communication module 210 includes dataassociated with the user (e.g., member profile data from an onlineaccount or social network service data) or other data to facilitate thefunctionality described herein.

The presentation module 220 provides various presentation and userinterface functionality operable to interactively present and receiveinformation to and from the user. For instance, the presentation module220 is used to manage output of image data with aligned and insertedvirtual objects, so that augmented reality images may be presented on adisplay. As mentioned above, these images may be presented in real-timeor near real-time as the images are captured, processed to add virtualobjects, and displayed with the virtual objects as quickly as possible.Presentation module 220 is also utilizable to present user interfaces,AR objects, or any such information generated in response to decoding anoptical barcode such as optical barcode 806 discussed below. In variousembodiments, the presentation module 220 presents or causes presentationof additional information (e.g., visually displaying information on ascreen, acoustic output, haptic feedback). The process of interactivelypresenting information is intended to include the exchange ofinformation between a particular device and the user. The user mayprovide input to interact with the user interface in many possiblemanners, such as alphanumeric, point based (e.g., cursor), tactile, orother input (e.g., touch screen, tactile sensor, light sensor, infraredsensor, biometric sensor, microphone, gyroscope, accelerometer, or othersensors). The presentation module 220 provides many other userinterfaces to facilitate functionality described herein. The term“presenting” as used herein is intended to include communicatinginformation or instructions to a particular device that is operable toperform presentation based on the communicated information orinstructions. This may include both output on a screen as well asprojection of an image onto a user's eye.

The configuration module 230 may be used to accept and manage userselection of system options. This may include options to select variousaugmented reality selections, including enabling augmented reality andrequesting certain types of augmented reality information to be providedor triggered based on user inputs or input based triggers. For example,configuration module 230 may include a setting provided by a user toautomatically present information about certain types of locations whenthe locations are identified in an image based location system or a mappositioning system. Configuration module 230 may also accept usersettings to automatically provide direction information in an augmentedreality image when direction input triggers are received viacommunication module 210. In other embodiments, any other triggers forimplementing image based location or augmented reality images may bemanaged by configuration module 230. For example, the configurationmodule 230 extracts and analyzes candidate shape features or candidatecontour characteristics from image data of the image received from theuser device (e.g., the client devices 110) when a system includes suchanalysis as a trigger for display of augmented reality images. Theconfiguration module 230 determines satisfaction of various rules orcriteria associated with the extracted candidate shape features. Theconfiguration module 230 compares the extracted candidate shape featureswith reference shape features of the custom graphic or another referenceimage. The configuration module 230 can employ a wide variety of schemesand techniques to extract candidate shape features from the image dataof the image and subsequently trigger display of augmented realityimages.

The alignment module 240 provides image processing functionality todetermine and verify an alignment of the image data captured by an imagesensor and the virtual objects placed into the image. In someembodiments, alignment module 240 may access or generate a computermodel of the environment, and may use the computer model to insertvirtual items into an image based on the computer model of theenvironment. In some embodiments, alignment module 240 calculate thescene's depth and surface information. In some embodiments, the computeris a digital three dimensional (3D) representation in the form of a 3Dscan.

In some embodiments, alignment module 240 may perform threshold or rulechecks to verify that virtual items displayed in augmented realityimages meet certain quality metrics to provide an acceptable userexperience. This may include verifying that a virtual object does notmove in unexpected ways with respect to objects in an image, that imagescaptured by an image sensor are sufficiently stable over time to enableaugmented reality functions, or other such metrics. In some embodiments,the alignment module 240 extracts spatial attributes from the imagedata. In various embodiments, the spatial attributes include at leastone of position, orientation, scale, or other spatial aspects of objectsin images. The alignment module 240 determines an alignment of the imageobjects based on the spatial attributes (e.g., a particularorientation). In an example, the alignment module 240 can determine analignment including position and orientation based on the spatialattributes and generate a transformed image according to the alignment.

The virtual item module 250 provides functionality to generate imagesassociated with virtual items. In some embodiments, this may includegraphics information related to virtual location markers, virtualdirection arrows, or virtual items or objects. In some embodiments, thismay include graphics information for inserting mobile virtual objectsinto video (e.g., virtual animals, robots, dinosaurs, video display,etc.). In some embodiments, for each virtual object, presentation rulesmay be stored in virtual item module 250 and used by other modules toverify that virtual objects may be inserted into image data withsufficient output quality.

The analysis module 260 provides functionality to perform a variety ofimage processing operations. Such operations may include imageprocessing operations to identify key points in an image and to matchtwo-dimensional façade data against portions of an image to identify amatch. For example, in some embodiments, analysis module 260 may acceptan image and identify building corners or other key points in the imagethat may contain two-dimensional pattern data as part of a façade.Analysis module 260 may then take façade data from a model and match theportion of the image to a building façade model included in the façadedata. In some embodiments, if no match is found, an analysis module 260operating on a client device 110 may request additional information oradditional processing by an analysis module 260 operating on a remoteserver, such as a third party server 120 or a server that is part of asocial messaging system 130.

The map positioning system 270 provides map data including associationsbetween map locations and façade data associated with buildings in alocation, or any other such information in a system. Map positioningsystem 270 may also interface with remote servers or systems, which mayprovide this information.

Image based location system 161 may comprise modules to accept streetview images from any number of sources and analyze the images togenerate façade data. Such façade data may include two-dimensionalestimates of certain patterns on a building, as well as key pointinformation for simple building locations, such as the locations ofbuilding corners or corners of two-dimensional façade patterns on abuilding. In some embodiments, information from multiple images may beused to generate façade data for a single building. Such informationfrom multiple images may be used to match colors in different lightingsituations, or to match minor changes over time to a building façade. Insome embodiments, specialized image and location capture equipment maybe used to generate information about building locations, keypoints ofbuildings, and building façade data with high accuracy in order to builda database of outdoor images of buildings in order to provide accuratereferences for image based location systems. Capturing locations ofbuilding corners, for example, with high accuracy (e.g., accuracy on theorder of single digit centimeters or millimeters) provides a basis foran image based location estimate for a camera position with similarerrors. In some embodiments, determining a camera position within a fewcentimeters (e.g., 5 cm) is sufficient to provide augmented realitypresentation with a low chance of clear errors in the output images thatbreak the reality illusion of augmented reality images.

In some embodiments, image based location system 161 may be distributedover a local client device and a remote server, with low informationfaçade models (e.g., models with low-resolution and/or low colortwo-dimensional façade data and a small number of keypoints) storedlocally on a device for regularly visited locations, expected futuretravel locations, or for buildings which the system believes might benear a device in the future. High information models (e.g., highresolution, high color information, and/or high numbers ofthree-dimensional keypoints) may be stored remotely and used when localcompact façade models fail. Image based location system 161 may manageapplication of façade data and models to match portions of capturedimages using analysis module 260. Once a match is found using analysismodule 260, location information related to a building matching façadedata or keypoints in a building may be used to calculate a relativeposition of the camera perspective in a captured image. This relativeposition may be used to determine an absolute position based on theposition of building keypoints or other absolute position informationthat is part of a façade or other model for a building associated withfaçade data.

Any one or more of the modules described may be implemented usinghardware alone (e.g., one or more of the processors 1204 of a machine)or a combination of hardware and software. For example, any moduledescribed of the AR system 124 may physically include an arrangement ofone or more of the processors 1204 (e.g., a subset of or among the oneor more processors of the machine) configured to perform the operationsdescribed herein for that module. As another example, any module of theAR system 124 may include software, hardware, or both, that configure anarrangement of one or more processors 1204 (e.g., among the one or moreprocessors of the machine) to perform the operations described hereinfor that module. Accordingly, different modules of the AR system 124 mayinclude and configure different arrangements of such processors 1204 ora single arrangement of such processors 1204 at different points intime. Moreover, any two or more modules of the AR system 124 may becombined into a single module, and the functions described herein for asingle module may be subdivided among multiple modules. Furthermore,according to various example embodiments, modules described herein asbeing implemented within a single machine, database, or device may bedistributed across multiple machines, databases, or devices.

FIG. 7 is a schematic diagram for explaining an example augmentedreality system according to some example embodiments. As shown in FIG.7, light source 140 projects of a pattern of light onto a scene 740. Insome embodiments, the light source 140 is a projector. In someembodiments, the light source 140 is a light emitting diode (LED). Insome embodiments, the AR system also includes a mask includingtransparent areas and opaque areas, the mask modulating an intensity oflight from the light source to project the pattern onto the scene 740,and an optical lens that projects light from light source 140 onto thescene 740 (e.g., 730 a, 730 b). The camera 130 captures an image of thescene including the projected pattern.

As previously discussed, light source 140 and camera 130 have a fixedgeometrical relationship to each other. In some embodiments, a distance170 between a location of the light source 140 and a location of thecamera 130 is between 5 mm to 10 mm. In some embodiments, a distance 170between location of the light source 140 and a location of the camera130 is 5 mm to 50 mm. In some embodiments, the distance 170 between alocation of the light source and a location of the camera is 20 mm.

A projector pixel of the pattern projected by light source 140 isdetermined that corresponds to an image pixel of the image captured bycamera 130. A disparity of each correspondence is determined, thedisparity being an amount that corresponding pixels are displacedbetween the projected pattern and the captured image.

Disparity is captured by following equation.I(x,y)=ρ(x,y)P(x+u(x,y),y)  (equation 1)

In equation 1, P(x, y) represents the projected pattern; ρ(x, y)represents a scaling (albedo) factor representing texture of the scene;u(x, y) represents the disparity. The geometry of the scene (e.g., depthof the scene) is estimated based on the disparity u(x, y).

Assuming the disparity is small, a first order approximation isperformed:I(x,y)=ρ(x,y)P(x,y)+U(x,y)P _(x)(x,y)  (equation 2)U(x,y)=ρ(x,y)u(x,y)  (equation 3)

In equations 2 and 3, I(x, y) represents the image captured by thecamera 130; ρ(x, y) represents texture of the scene (albedo factor);P(x, y) represents the pattern projected onto the scene by light source140; P_(x) (x, y) represents the derivative of the projected patternalong the horizontal direction; u(x, y) represents the disparity; U(x,y) is the product of the albedo factor multiplied by the disparity.

Assuming over a small n×n window that the albedo factor ρ(x, y) isconstant and the disparity u(x, y) is constant, the following matrix isgenerated.

$\begin{matrix}{{\begin{bmatrix}{{P_{x}\left( {x_{1},y_{1}} \right)}{P\left( {x_{1},y_{1}} \right)}} \\{{P_{x}\left( {x_{k},y_{l}} \right)}{P\left( {x_{k},y_{l}} \right)}} \\. \\. \\. \\{{P_{x}\left( {x_{n},y_{n}} \right)}{P\left( {x_{n},y_{n}} \right)}}\end{bmatrix}\begin{bmatrix}u_{0} \\\rho_{0}\end{bmatrix}} = \begin{bmatrix}{I\left( {x_{1},y_{1}} \right)} \\{I\left( {x_{k},y_{l}} \right)} \\{I\left( {x_{n},y_{n}} \right)}\end{bmatrix}} & \left( {{equation}\mspace{14mu} 4} \right) \\{A = \begin{bmatrix}{{P_{x}\left( {x_{1},y_{1}} \right)}{P\left( {x_{1},y_{1}} \right)}} \\{{P_{x}\left( {x_{k},y_{l}} \right)}{P\left( {x_{k},y_{l}} \right)}} \\. \\. \\. \\{{P_{x}\left( {x_{n},y_{n}} \right)}{P\left( {x_{n},y_{n}} \right)}}\end{bmatrix}} & \left( {{equation}\mspace{14mu} 5} \right) \\{u = \begin{bmatrix}u_{0} \\\rho_{0}\end{bmatrix}} & \left( {{equation}\mspace{14mu} 6} \right) \\{I_{c} = \begin{bmatrix}{I\left( {x_{1},y_{1}} \right)} \\{I\left( {x_{k},y_{l}} \right)} \\{I\left( {x_{n},y_{n}} \right)}\end{bmatrix}} & \left( {{equation}\mspace{14mu} 7} \right)\end{matrix}$

In equations 4 to 6, Ic represents the camera observations (e.g., acollection of intensities of the camera 130); matrix A is formed byintensities of the light source 140; the first column of matrix Arepresents the derivative of the projector intensities; the secondcolumn of matrix A represents the values of the projected patternitself; the matrix u is to be estimated.

In order to determine a pattern to project, the following equation isexamined:Au=I _(c)  (equation 8)

Both sides of equation 8 are multiplied by the transpose of matrix A:A ^(T) Au=A ^(T) I _(c)  (equation 9)

Resulting in the following micro-baseline structured light (MSL) matrix:

$\begin{matrix}{{\begin{pmatrix}{\left\langle {I_{p}^{x},I_{p}^{x}} \right\rangle\left\langle {I_{p},I_{p}^{x}} \right\rangle} \\{\left\langle {I_{p},I_{p}^{x}} \right\rangle\left\langle {I_{p},I_{p}} \right\rangle}\end{pmatrix}\begin{pmatrix}u_{0} \\\rho_{0}\end{pmatrix}} = \begin{pmatrix}\left\langle {I_{p},I_{c}} \right\rangle \\\left\langle {I_{p}^{x},I_{c}} \right\rangle\end{pmatrix}} & \left( {{equation}\mspace{14mu} 10} \right)\end{matrix}$

In equation 10,

I_(p), I_(c)

represents the inner product between camera intensities Ic and projectorintensities Ip;

I_(p) ^(x), I_(c)

represents the inner product between camera intensities Ic and thederivative of the projector intensities I_(p) ^(x).

One advantage of the MSL matrix of equation 10 is that it depends solelyon the pattern projected onto the scene. In order to determine a patternsuch that the MSL matrix is inverted, a condition number is minimized.For example, the cross-diagonal limits of the MSL matrix are minimized,such that a variance in solution (ambiguity) is lowered. An variance insolution is, for example, a scene depth that is indicated as a couple ofinches or a couple of hundred inches away. In the MSL matrix, thecross-diagonal limits are the two terms:

I_(p), I_(p) ^(x)

;

I_(p), I_(p) ^(x)

.

The following conditions are imposed:

(1) The projected pattern is periodic (e.g., sinusoids, piecewiselinear) with period equal to the window size (n). This provides asolution that has low variance; and

(2) P(x₁, y)=P(x_(n), y).

Now, invariance to tilted planes in the scene (e.g., tables, walls,chairs) will be considered. In the foregoing, disparity has been assumedto be constant over a small n×n window. That condition is now relaxed,and it is assumed that disparity is linearly varying over the small n×nwindow:u=ax+b  (equation 11)

This provide that the estimated disparity is approximately equal to theoriginal disparity, and this estimate is invariant to the tilt of theplane:u ₀=mean(u)  (equation 12)

The invariance to tilted planes is provided for if the derivative is+/−constant (l_(x)(x,y)=+constant). The projected patterns are thereforedetermined to be piecewise linear.

In order to maximize the signal to noise ratio (SNR, the diagonal limitsof the MSL matrix

I_(p) ^(x), I_(p) ^(x)

and

I_(p), I_(p)

are maximized. It is therefore determined that the projected patternshould be a triangular pattern, such as the pattern 820 illustrated inFIG. 8. The pattern 820 can have a window size of n or 2n.

Selection of the window size is now discussed with reference to FIG. 9.As illustrated in FIG. 9, a light source 140 projects a pattern of light930. The appropriate window size is determined based on the target rangeof depths (e.g., 910, 920) of the scene. In the context of a mobiledevice, this is, for example, approximately more than 2 feet away fromthe camera and approximately less than 10 feet away from the camera. Insome embodiments, the window size n is selected to be greater than agreatest disparity that is estimated based on a target depth range ofthe scene (n≥u_max). The greatest disparity is the largest amount thatcorresponding pixels are displaced between the projected pattern and thecaptured image. In some embodiments, the window size can be a factor ofn (kn).

In embodiments where a scene is highly textured, window size is adjustedand adapted to the scene (e.g., the window size is not fixed). Forexample, the window size can be made larger to encompass a highlytextured area of the scene. In such embodiments, a constant disparitycan be assigned for an entire area having similar characteristics.

FIG. 10 is a flow chart for explaining a method of projecting structuredlight to recover three-dimensional data according to some exampleembodiments. Operations of the method 1000 may be performed by themodules described above with respect to FIG. 6. As shown in FIG. 10, themethod 1000 includes one or more blocks 1001, 1002, 1003, 1004, 1005 and1006.

At block 1001, the light source projects a pattern of light onto ascene. In some embodiments, the pattern is periodic. The period of thepattern is equal to the window size for determining disparity. In someembodiments, the projected pattern is a triangular pattern.

At block 1002, the camera captures an image of the scene including theprojected pattern.

At block 1003, a correspondence is determined between an image pixel ofthe captured image and a projector pixel of the projected pattern.

At block 1004, a disparity of each correspondence is determined. Thedisparity is an amount that corresponding pixels are displaced betweenthe projected pattern and the captured image.

The window size of a window for determining the disparity is greaterthan a greatest disparity that is estimated based on a target depthrange of the scene. The greatest disparity is the largest amount thatcorresponding pixels are displaced between the projected pattern and thecaptured image.

At block 1005, one or more processors generates a three-dimensionalcomputer model of the scene based on the disparity.

At block 1006, a virtual object is rendered in the scene based on thethree-dimensional computer model. In some embodiments, the computermodel comprises a depth map. In some embodiments, the computer modelcomprises a video rate depth map.

By virtue of the method described above, even with a small footprint(small distance between the camera and light source) it is possible touse structured light to obtain depth information about a scene. Inaddition, it is possible to do so computationally quickly.

In some embodiments, in order to compensate for ambient light in thescene (e.g., separate ambient light from the captured image), the ARsystem also causes the camera to capture an image of the scene withoutthe projected pattern. A difference is determined between the imagecaptured including the projected pattern and the image captured withoutthe projected pattern to obtain an image of the scene including theprojected pattern but without ambient light. In some embodiments,capturing the image of the scene including the projected pattern,capturing the image of the scene without the projected pattern, anddetermining the difference are performed at a frame rate equal to aframe rate of the camera (e.g., 60 fps). This allows for generation ofdepth maps at half the frame rate of the camera (e.g, 30 fps) and apattern free video at half the frame rate of the camera (e.g, 30 fps),the pattern free video being free of the projected pattern. In someembodiments, a video rate depth map is provided comprising a depth mapthat is at video rate.

Software Architecture

FIG. 11 is a block diagram illustrating an example software architecture1106, which may be used in conjunction with various hardwarearchitectures herein described. FIG. 11 is a non-limiting example of asoftware architecture and it will be appreciated that many otherarchitectures may be implemented to facilitate the functionalitydescribed herein. The software architecture 1106 may execute on hardwaresuch as machine 700 of FIG. 11 that includes, among other things,processors 1104, memory 1114, and I/O components 1118. A representativehardware layer 1152 is illustrated and can represent, for example, themachine 1100 of FIG. 11. The representative hardware layer 1152 includesa processing unit 1154 having associated executable instructions 1104.Executable instructions 1104 represent the executable instructions ofthe software architecture 1106, including implementation of the methods,components and so forth described herein. The hardware layer 1152 alsoincludes memory and/or storage modules memory/storage 1156, which alsohave executable instructions 1104. The hardware layer 1152 may alsocomprise other hardware 1158.

In the example architecture of FIG. 11, the software architecture 1106may be conceptualized as a stack of layers where each layer providesparticular functionality. For example, the software architecture 1106may include layers such as an operating system 1102, libraries 1120,applications 1116 and a presentation layer 1114. Operationally, theapplications 1116 and/or other components within the layers may invokeapplication programming interface (API) API calls 1108 through thesoftware stack and receive a response as in response to the API calls1108. The layers illustrated are representative in nature and not allsoftware architectures have all layers. For example, some mobile orspecial purpose operating systems may not provide aframeworks/middleware 1118, while others may provide such a layer. Othersoftware architectures may include additional or different layers.

The operating system 1102 may manage hardware resources and providecommon services. The operating system 1102 may include, for example, akernel 1122, services 1124 and drivers 1126. The kernel 1122 may act asan abstraction layer between the hardware and the other software layers.For example, the kernel 1122 may be responsible for memory management,processor management (e.g., scheduling), component management,networking, security settings, and so on. The services 1124 may provideother common services for the other software layers. The drivers 1126are responsible for controlling or interfacing with the underlyinghardware. For instance, the drivers 1126 include display drivers, cameradrivers, Bluetooth® drivers, flash memory drivers, serial communicationdrivers (e.g., Universal Serial Bus (USB) drivers), Wi-Fi® drivers,audio drivers, power management drivers, and so forth depending on thehardware configuration.

The libraries 1120 provide a common infrastructure that is used by theapplications 1116 and/or other components and/or layers. The libraries1120 provide functionality that allows other software components toperform tasks in an easier fashion than to interface directly with theunderlying operating system 1102 functionality (e.g., kernel 1122,services 1124 and/or drivers 1126). The libraries 1120 may includesystem libraries 1144 (e.g., C standard library) that may providefunctions such as memory allocation functions, string manipulationfunctions, mathematical functions, and the like. In addition, thelibraries 1120 may include API libraries 1146 such as media libraries(e.g., libraries to support presentation and manipulation of variousmedia format such as MPREG4, H.264, MP3, AAC, AMR, JPG, PNG), graphicslibraries (e.g., an OpenGL framework that may be used to render 2D and3D in a graphic content on a display), database libraries (e.g., SQLitethat may provide various relational database functions), web libraries(e.g., WebKit that may provide web browsing functionality), and thelike. The libraries 1120 may also include a wide variety of otherlibraries 1148 to provide many other APIs to the applications 1116 andother software components/modules.

The frameworks/middleware 1118 (also sometimes referred to asmiddleware) provide a higher-level common infrastructure that may beused by the applications 1116 and/or other software components/modules.For example, the frameworks/middleware 1118 may provide various graphicuser interface (GUI) functions, high-level resource management,high-level location services, and so forth. The frameworks/middleware1118 may provide a broad spectrum of other APIs that may be utilized bythe applications 1116 and/or other software components/modules, some ofwhich may be specific to a particular operating system 1102 or platform.

The applications 1116 include built-in applications 1138 and/orthird-party applications 1140. Examples of representative built-inapplications 1138 may include, but are not limited to, a contactsapplication, a browser application, a book reader application, alocation application, a media application, a messaging application,and/or a game application. Third-party applications 1140 may include anapplication developed using the ANDROID™ or IOS™ software developmentkit (SDK) by an entity other than the vendor of the particular platform,and may be mobile software running on a mobile operating system such asIOS™, ANDROID™, WINDOWS® Phone, or other mobile operating systems. Thethird-party applications 1140 may invoke the API calls 1108 provided bythe mobile operating system (such as operating system 1102) tofacilitate functionality described herein.

The applications 1116 may use built in operating system functions (e.g.,kernel 1122, services 1124 and/or drivers 1126), libraries 1120, andframeworks/middleware 1118 to create user interfaces to interact withusers of the system. Alternatively, or additionally, in some systemsinteractions with a user may occur through a presentation layer, such aspresentation layer 1114. In these systems, the application/component“logic” can be separated from the aspects of the application/componentthat interact with a user.

FIG. 12 is a block diagram illustrating components of a machine 1200,according to some example embodiments, able to read instructions from amachine-readable medium (e.g., a machine-readable storage medium) andperform any one or more of the methodologies discussed herein.Specifically, FIG. 12 shows a diagrammatic representation of the machine1200 in the example form of a computer system, within which instructions1210 (e.g., software, a program, an application, an applet, an app, orother executable code) for causing the machine 1200 to perform any oneor more of the methodologies discussed herein may be executed. As such,the instructions 1210 may be used to implement modules or componentsdescribed herein. The instructions 1210 transform the general,non-programmed machine 1200 into a particular machine 1200 programmed tocarry out the described and illustrated functions in the mannerdescribed. In alternative embodiments, the machine 1200 operates as astandalone device or may be coupled (e.g., networked) to other machines.In a networked deployment, the machine 1200 may operate in the capacityof a server machine or a client machine in a server-client networkenvironment, or as a peer machine in a peer-to-peer (or distributed)network environment. The machine 1200 may comprise, but not be limitedto, a server computer, a client computer, a personal computer (PC), atablet computer, a laptop computer, a netbook, a set-top box (STB), apersonal digital assistant (PDA), an entertainment media system, acellular telephone, a smart phone, a mobile device, a wearable device(e.g., a smart watch), a smart home device (e.g., a smart appliance),other smart devices, a web appliance, a network router, a networkswitch, a network bridge, or any machine capable of executing theinstructions 1210, sequentially or otherwise, that specify actions to betaken by machine 1200. Further, while only a single machine 1200 isillustrated, the term “machine” shall also be taken to include acollection of machines that individually or jointly execute theinstructions 1210 to perform any one or more of the methodologiesdiscussed herein.

The machine 1200 may include processors 1204, memory memory/storage1206, and I/O components 1218, which may be configured to communicatewith each other such as via a bus 1202. The memory/storage 1206 mayinclude a memory 1214, such as a main memory, or other memory storage,and a storage unit 1216, both accessible to the processors 1204 such asvia the bus 1202. The storage unit 1216 and memory 1214 store theinstructions 1210 embodying any one or more of the methodologies orfunctions described herein. The instructions 1210 may also reside,completely or partially, within the memory 1214, within the storage unit1216, within at least one of the processors 1204 (e.g., within theprocessor's cache memory), or any suitable combination thereof, duringexecution thereof by the machine 1200. Accordingly, the memory 1214, thestorage unit 1216, and the memory of processors 1204 are examples ofmachine-readable media.

The I/O components 1218 may include a wide variety of components toreceive input, provide output, produce output, transmit information,exchange information, capture measurements, and so on. The specific I/Ocomponents 1218 that are included in a particular machine 1200 willdepend on the type of machine. For example, portable machines such asmobile phones will likely include a touch input device or other suchinput mechanisms, while a headless server machine will likely notinclude such a touch input device. It will be appreciated that the I/Ocomponents 1218 may include many other components that are not shown inFIG. 12. The I/O components 1218 are grouped according to functionalitymerely for simplifying the following discussion and the grouping is inno way limiting. In various example embodiments, the I/O components 1218may include output components 1226 and input components 1228. The outputcomponents 1226 may include visual components (e.g., a display such as aplasma display panel (PDP), a light emitting diode (LED) display, aliquid crystal display (LCD), a projector, or a cathode ray tube (CRT)),acoustic components (e.g., speakers), haptic components (e.g., avibratory motor, resistance mechanisms), other signal generators, and soforth. The input components 1228 may include alphanumeric inputcomponents (e.g., a keyboard, a touch screen configured to receivealphanumeric input, a photo-optical keyboard, or other alphanumericinput components), point based input components (e.g., a mouse, atouchpad, a trackball, a joystick, a motion sensor, or other pointinginstrument), tactile input components (e.g., a physical button, a touchscreen that provides location and/or force of touches or touch gestures,or other tactile input components), audio input components (e.g., amicrophone), and the like.

In further example embodiments, the I/O components 1218 may includebiometric components 1230, motion components 1234, environmentalenvironment components 1236, or position components 1238 among a widearray of other components. For example, the biometric components 1230may include components to detect expressions (e.g., hand expressions,facial expressions, vocal expressions, body gestures, or eye tracking),measure biosignals (e.g., blood pressure, heart rate, body temperature,perspiration, or brain waves), identify a person (e.g., voiceidentification, retinal identification, facial identification,fingerprint identification, or electroencephalogram basedidentification), and the like. The motion components 1234 may includeacceleration sensor components (e.g., accelerometer), gravitation sensorcomponents, rotation sensor components (e.g., gyroscope), and so forth.The environment components 1236 may include, for example, illuminationsensor components (e.g., photometer), temperature sensor components(e.g., one or more thermometer that detect ambient temperature),humidity sensor components, pressure sensor components (e.g.,barometer), acoustic sensor components (e.g., one or more microphonesthat detect background noise), proximity sensor components (e.g.,infrared sensors that detect nearby objects), gas sensors (e.g., gasdetection sensors to detection concentrations of hazardous gases forsafety or to measure pollutants in the atmosphere), or other componentsthat may provide indications, measurements, or signals corresponding toa surrounding physical environment. The position components 1238 mayinclude location sensor components (e.g., a Global Position system (GPS)receiver component), altitude sensor components (e.g., altimeters orbarometers that detect air pressure from which altitude may be derived),orientation sensor components (e.g., magnetometers), and the like.

Communication may be implemented using a wide variety of technologies.The I/O components 1218 may include communication components 1240operable to couple the machine 1200 to a network 1232 or devices 1220via coupling 1222 and coupling 1224 respectively. For example, thecommunication components 1240 may include a network interface componentor other suitable device to interface with the network 1232. In furtherexamples, communication components 1240 may include wired communicationcomponents, wireless communication components, cellular communicationcomponents, Near Field Communication (NFC) components, Bluetooth®components (e.g., Bluetooth® Low Energy), Wi-Fi® components, and othercommunication components to provide communication via other modalities.The devices 1220 may be another machine or any of a wide variety ofperipheral devices (e.g., a peripheral device coupled via a UniversalSerial Bus (USB)).

Moreover, the communication components 1240 may detect identifiers orinclude components operable to detect identifiers. For example, thecommunication components 1240 may include Radio Frequency Identification(RFID) tag reader components, NFC smart tag detection components,optical reader components (e.g., an optical sensor to detectone-dimensional bar codes such as Universal Product Code (UPC) bar code,multi-dimensional bar codes such as Quick Response (QR) code, Azteccode, Data Matrix, Dataglyph, MaxiCode, PDF417, Ultra Code, UCC RSS-2Dbar code, and other optical codes), or acoustic detection components(e.g., microphones to identify tagged audio signals). In addition, avariety of information may be derived via the communication components1240, such as, location via Internet Protocol (IP) geo-location,location via Wi-Fi® signal triangulation, location via detecting a NFCbeacon signal that may indicate a particular location, and so forth.

Certain embodiments are described herein as including logic or a numberof components, modules, or mechanisms. Modules can constitute eithersoftware modules (e.g., code embodied on a machine-readable medium) orhardware modules. A “hardware module” is a tangible unit capable ofperforming certain operations and can be configured or arranged in acertain physical manner. In various example embodiments, one or morecomputer systems (e.g., a standalone computer system, a client computersystem, or a server computer system) or one or more hardware modules ofa computer system (e.g., a processor or a group of processors) can beconfigured by software (e.g., an application or application portion) asa hardware module that operates to perform certain operations asdescribed herein.

In some embodiments, a hardware module can be implemented mechanically,electronically, or any suitable combination thereof. For example, ahardware module can include dedicated circuitry or logic that ispermanently configured to perform certain operations. For example, ahardware module can be a special-purpose processor, such as aField-Programmable Gate Array (FPGA) or an Application SpecificIntegrated Circuit (ASIC). A hardware module may also includeprogrammable logic or circuitry that is temporarily configured bysoftware to perform certain operations. For example, a hardware modulecan include software executed by a general-purpose processor or otherprogrammable processor. Once configured by such software, hardwaremodules become specific machines (or specific components of a machine)uniquely tailored to perform the configured functions and are no longergeneral-purpose processors. It will be appreciated that the decision toimplement a hardware module mechanically, in dedicated and permanentlyconfigured circuitry, or in temporarily configured circuitry (e.g.,configured by software) can be driven by cost and time considerations.

Accordingly, the phrase “hardware module” should be understood toencompass a tangible entity, be that an entity that is physicallyconstructed, permanently configured (e.g., hardwired), or temporarilyconfigured (e.g., programmed) to operate in a certain manner or toperform certain operations described herein. As used herein,“hardware-implemented module” refers to a hardware module. Consideringembodiments in which hardware modules are temporarily configured (e.g.,programmed), each of the hardware modules need not be configured orinstantiated at any one instance in time. For example, where a hardwaremodule comprises a general-purpose processor configured by software tobecome a special-purpose processor, the general-purpose processor may beconfigured as respectively different special-purpose processors (e.g.,comprising different hardware modules) at different times. Softwareaccordingly configures a particular processor or processors, forexample, to constitute a particular hardware module at one instance oftime and to constitute a different hardware module at a differentinstance of time.

Hardware modules can provide information to, and receive informationfrom, other hardware modules. Accordingly, the described hardwaremodules can be regarded as being communicatively coupled. Where multiplehardware modules exist contemporaneously, communications can be achievedthrough signal transmission (e.g., over appropriate circuits and buses)between or among two or more of the hardware modules. In embodiments inwhich multiple hardware modules are configured or instantiated atdifferent times, communications between such hardware modules may beachieved, for example, through the storage and retrieval of informationin memory structures to which the multiple hardware modules have access.For example, one hardware module can perform an operation and store theoutput of that operation in a memory device to which it iscommunicatively coupled. A further hardware module can then, at a latertime, access the memory device to retrieve and process the storedoutput. Hardware modules can also initiate communications with input oroutput devices, and can operate on a resource (e.g., a collection ofinformation).

The various operations of example methods described herein can beperformed, at least partially, by one or more processors that aretemporarily configured (e.g., by software) or permanently configured toperform the relevant operations. Whether temporarily or permanentlyconfigured, such processors constitute processor-implemented modulesthat operate to perform one or more operations or functions describedherein. As used herein, “processor-implemented module” refers to ahardware module implemented using one or more processors.

Similarly, the methods described herein can be at least partiallyprocessor-implemented, with a particular processor or processors beingan example of hardware. For example, at least some of the operations ofa method can be performed by one or more processors orprocessor-implemented modules. Moreover, the one or more processors mayalso operate to support performance of the relevant operations in a“cloud computing” environment or as a “software as a service” (SaaS).For example, at least some of the operations may be performed by a groupof computers (as examples of machines including processors), with theseoperations being accessible via a network (e.g., the Internet) and viaone or more appropriate interfaces (e.g., an API).

The performance of certain of the operations may be distributed amongthe processors, not only residing within a single machine, but deployedacross a number of machines. In some example embodiments, the processorsor processor-implemented modules can be located in a single geographiclocation (e.g., within a home environment, an office environment, or aserver farm). In other example embodiments, the processors orprocessor-implemented modules are distributed across a number ofgeographic locations.

The modules, methods, applications and so forth described in conjunctionwith the figures above are implemented in some embodiments in thecontext of a machine and an associated software architecture. Thesections below describe representative software architecture(s) andmachine (e.g., hardware) architecture that are suitable for use with thedisclosed embodiments.

Software architectures are used in conjunction with hardwarearchitectures to create devices and machines tailored to particularpurposes. For example, a particular hardware architecture coupled with aparticular software architecture will create a mobile device, such as amobile phone, tablet device, or so forth. A slightly different hardwareand software architecture may yield a smart device for use in the“internet of things.” While yet another combination produces a servercomputer for use within a cloud computing architecture. Not allcombinations of such software and hardware architectures are presentedhere as those of skill in the art can readily understand how toimplement the invention in different contexts from the disclosurecontained herein.

Glossary

“CARRIER SIGNAL” in this context refers to any intangible medium that iscapable of storing, encoding, or carrying instructions for execution bythe machine, and includes digital or analog communications signals orother intangible medium to facilitate communication of suchinstructions. Instructions may be transmitted or received over thenetwork using a transmission medium via a network interface device andusing any one of a number of well-known transfer protocols.

“CLIENT DEVICE” in this context refers to any machine that interfaces toa communications network to obtain resources from one or more serversystems or other client devices. A client device may be, but is notlimited to, a mobile phone, desktop computer, laptop, portable digitalassistants (PDAs), smart phones, tablets, ultra books, netbooks,laptops, multi-processor systems, microprocessor-based or programmableconsumer electronics, game consoles, set-top boxes, or any othercommunication device that a user may use to access a network.

“COMMUNICATIONS NETWORK” in this context refers to one or more portionsof a network that may be an ad hoc network, an intranet, an extranet, avirtual private network (VPN), a local area network (LAN), a wirelessLAN (WLAN), a wide area network (WAN), a wireless WAN (WWAN), ametropolitan area network (MAN), the Internet, a portion of theInternet, a portion of the Public Switched Telephone Network (PSTN), aplain old telephone service (POTS) network, a cellular telephonenetwork, a wireless network, a Wi-Fi® network, another type of network,or a combination of two or more such networks. For example, a network ora portion of a network may include a wireless or cellular network andthe coupling may be a Code Division Multiple Access (CDMA) connection, aGlobal System for Mobile communications (GSM) connection, or other typeof cellular or wireless coupling. In this example, the coupling mayimplement any of a variety of types of data transfer technology, such asSingle Carrier Radio Transmission Technology (1×RTT), Evolution-DataOptimized (EVDO) technology, General Packet Radio Service (GPRS)technology, Enhanced Data rates for GSM Evolution (EDGE) technology,third Generation Partnership Project (3GPP) including 3G, fourthgeneration wireless (4G) networks, Universal Mobile TelecommunicationsSystem (UMTS), High Speed Packet Access (HSPA), WorldwideInteroperability for Microwave Access (WiMAX), Long Term Evolution (LTE)standard, others defined by various standard setting organizations,other long range protocols, or other data transfer technology.

“EMPHEMERAL MESSAGE” in this context refers to a message that isaccessible for a time-limited duration. An ephemeral message may be atext, an image, a video and the like. The access time for the ephemeralmessage may be set by the message sender. Alternatively, the access timemay be a default setting or a setting specified by the recipient.Regardless of the setting technique, the message is transitory.

“MACHINE-READABLE MEDIUM” in this context refers to a component, deviceor other tangible media able to store instructions and data temporarilyor permanently and may include, but is not be limited to, random-accessmemory (RAM), read-only memory (ROM), buffer memory, flash memory,optical media, magnetic media, cache memory, other types of storage(e.g., Erasable Programmable Read-Only Memory (EEPROM)) and/or anysuitable combination thereof. The term “machine-readable medium” shouldbe taken to include a single medium or multiple media (e.g., acentralized or distributed database, or associated caches and servers)able to store instructions. The term “machine-readable medium” shallalso be taken to include any medium, or combination of multiple media,that is capable of storing instructions (e.g., code) for execution by amachine, such that the instructions, when executed by one or moreprocessors of the machine, cause the machine to perform any one or moreof the methodologies described herein. Accordingly, a “machine-readablemedium” refers to a single storage apparatus or device, as well as“cloud-based” storage systems or storage networks that include multiplestorage apparatus or devices. The term “machine-readable medium”excludes signals per se.

“COMPONENT” in this context refers to a device, physical entity or logichaving boundaries defined by function or subroutine calls, branchpoints, application program interfaces (APIs), or other technologiesthat provide for the partitioning or modularization of particularprocessing or control functions. Components may be combined via theirinterfaces with other components to carry out a machine process. Acomponent may be a packaged functional hardware unit designed for usewith other components and a part of a program that usually performs aparticular function of related functions. Components may constituteeither software components (e.g., code embodied on a machine-readablemedium) or hardware components. A “hardware component” is a tangibleunit capable of performing certain operations and may be configured orarranged in a certain physical manner. In various example embodiments,one or more computer systems (e.g., a standalone computer system, aclient computer system, or a server computer system) or one or morehardware components of a computer system (e.g., a processor or a groupof processors) may be configured by software (e.g., an application orapplication portion) as a hardware component that operates to performcertain operations as described herein. A hardware component may also beimplemented mechanically, electronically, or any suitable combinationthereof. For example, a hardware component may include dedicatedcircuitry or logic that is permanently configured to perform certainoperations. A hardware component may be a special-purpose processor,such as a Field-Programmable Gate Array (FPGA) or an ApplicationSpecific Integrated Circuit (ASIC). A hardware component may alsoinclude programmable logic or circuitry that is temporarily configuredby software to perform certain operations. For example, a hardwarecomponent may include software executed by a general-purpose processoror other programmable processor. Once configured by such software,hardware components become specific machines (or specific components ofa machine) uniquely tailored to perform the configured functions and areno longer general-purpose processors. It will be appreciated that thedecision to implement a hardware component mechanically, in dedicatedand permanently configured circuitry, or in temporarily configuredcircuitry (e.g., configured by software) may be driven by cost and timeconsiderations. Accordingly, the phrase “hardware component” (or“hardware-implemented component”) should be understood to encompass atangible entity, be that an entity that is physically constructed,permanently configured (e.g., hardwired), or temporarily configured(e.g., programmed) to operate in a certain manner or to perform certainoperations described herein. Considering embodiments in which hardwarecomponents are temporarily configured (e.g., programmed), each of thehardware components need not be configured or instantiated at any oneinstance in time. For example, where a hardware component comprises ageneral-purpose processor configured by software to become aspecial-purpose processor, the general-purpose processor may beconfigured as respectively different special-purpose processors (e.g.,comprising different hardware components) at different times. Softwareaccordingly configures a particular processor or processors, forexample, to constitute a particular hardware component at one instanceof time and to constitute a different hardware component at a differentinstance of time. Hardware components can provide information to, andreceive information from, other hardware components. Accordingly, thedescribed hardware components may be regarded as being communicativelycoupled. Where multiple hardware components exist contemporaneously,communications may be achieved through signal transmission (e.g., overappropriate circuits and buses) between or among two or more of thehardware components. In embodiments in which multiple hardwarecomponents are configured or instantiated at different times,communications between such hardware components may be achieved, forexample, through the storage and retrieval of information in memorystructures to which the multiple hardware components have access. Forexample, one hardware component may perform an operation and store theoutput of that operation in a memory device to which it iscommunicatively coupled. A further hardware component may then, at alater time, access the memory device to retrieve and process the storedoutput. Hardware components may also initiate communications with inputor output devices, and can operate on a resource (e.g., a collection ofinformation). The various operations of example methods described hereinmay be performed, at least partially, by one or more processors that aretemporarily configured (e.g., by software) or permanently configured toperform the relevant operations. Whether temporarily or permanentlyconfigured, such processors may constitute processor-implementedcomponents that operate to perform one or more operations or functionsdescribed herein. As used herein, “processor-implemented component”refers to a hardware component implemented using one or more processors.Similarly, the methods described herein may be at least partiallyprocessor-implemented, with a particular processor or processors beingan example of hardware. For example, at least some of the operations ofa method may be performed by one or more processors orprocessor-implemented components. Moreover, the one or more processorsmay also operate to support performance of the relevant operations in a“cloud computing” environment or as a “software as a service” (SaaS).For example, at least some of the operations may be performed by a groupof computers (as examples of machines including processors), with theseoperations being accessible via a network (e.g., the Internet) and viaone or more appropriate interfaces (e.g., an Application ProgramInterface (API)). The performance of certain of the operations may bedistributed among the processors, not only residing within a singlemachine, but deployed across a number of machines. In some exampleembodiments, the processors or processor-implemented components may belocated in a single geographic location (e.g., within a homeenvironment, an office environment, or a server farm). In other exampleembodiments, the processors or processor-implemented components may bedistributed across a number of geographic locations.

“PROCESSOR” in this context refers to any circuit or virtual circuit (aphysical circuit emulated by logic executing on an actual processor)that manipulates data values according to control signals (e.g.,“commands”, “op codes”, “machine code”, etc.) and which producescorresponding output signals that are applied to operate a machine. Aprocessor may, for example, be a Central Processing Unit (CPU), aReduced Instruction Set Computing (RISC) processor, a ComplexInstruction Set Computing (CISC) processor, a Graphics Processing Unit(GPU), a Digital Signal Processor (DSP), an Application SpecificIntegrated Circuit (ASIC), a Radio-Frequency Integrated Circuit (RFIC)or any combination thereof. A processor may further be a multi-coreprocessor having two or more independent processors (sometimes referredto as “cores”) that may execute instructions contemporaneously.

“TIMESTAMP” in this context refers to a sequence of characters orencoded information identifying when a certain event occurred, forexample giving date and time of day, sometimes accurate to a smallfraction of a second.

“LIFT” in this context is a measure of the performance of a targetedmodel at predicting or classifying cases as having an enhanced response(with respect to a population as a whole), measured against a randomchoice targeting model.

What is claimed is:
 1. A system comprising: a light source; a camera; amemory; and at least one hardware processor coupled to the memory andcomprising instructions that causes the system to perform operationscomprising: causing the light source to project of a pattern of lightonto a scene, wherein the pattern is periodic; causing the camera tocapture an image of the scene including the projected pattern;determining a projector pixel of the projected pattern corresponding toan image pixel of the captured image; determining a disparity of eachcorrespondence, the disparity being an amount that corresponding pixelsare displaced between the projected pattern and the captured image;generating, by one or more processors, a three-dimensional computermodel of the scene based on the disparity; causing the camera to capturean image of the scene without the projected pattern; and performingambient light compensation with respect to the captured image based on adifference between the image captured including the projected patternand the image captured without the projected pattern; and rendering avirtual object in the scene based on the three-dimensional computermodel and on the ambient light compensation.
 2. The system of claim 1wherein a distance between a location of the light source and a locationof the camera is from 5 mm to 10 mm.
 3. The system of claim 1 wherein awindow size of a window for determining the disparity is greater than agreatest disparity that is estimated based on a target depth range ofthe scene, the greatest disparity being the largest amount thatcorresponding pixels are displaced between the projected pattern and thecaptured image.
 4. The system of claim 3 wherein the period of thepattern is equal to the window size.
 5. The system of claim 1 whereinthe projected pattern is a triangular pattern.
 6. The system of claim 1further comprising: a mask including transparent areas and opaque areas,wherein the mask modulates an intensity of light from the light source;and a lens to project the pattern onto the scene.
 7. The system claim 1wherein the light source is a light emitting diode (LED).
 8. The systemof claim 1 wherein computer model comprises a depth map.
 9. The systemof claim 1 wherein the computer model comprises a video rate depth map.10. The system of claim 1 wherein causing the camera to capture theimage of the scene including the projected pattern, causing the camerato capture the image of the scene without the projected pattern, anddetermining the difference are performed at a frame rate equal to aframe rate of the camera to generate depth maps at half the frame rateof the camera and to generate a video at half the frame rate of thecamera, the video being free of the projected pattern.
 11. A methodcomprising: causing a light source to project of a pattern of light ontoa scene, wherein the pattern is periodic; causing a camera to capture animage of the scene including the projected pattern; determining aprojector pixel of the projected pattern corresponding to an image pixelof the captured image; determining a disparity of each correspondence,the disparity being an amount that corresponding pixels are displacedbetween the projected pattern and the captured image; generating, by oneor more processors, a three-dimensional computer model of the scenebased on the disparity; causing the camera to capture an image of thescene without the projected pattern; and performing ambient lightcompensation with respect to the captured image based on a differencebetween the image captured including the projected pattern and the imagecaptured without the projected pattern; and rendering a virtual objectin the scene based on the three-dimensional computer model and on theambient light compensation.
 12. The method of claim 11 wherein adistance between a location of the light source and a location of thecamera is from 5 mm to 10 mm.
 13. The method of claim 11 wherein awindow size of a window for determining the disparity is greater than agreatest disparity that is estimated based on a target depth range ofthe scene, the greatest disparity being the largest amount thatcorresponding pixels are displaced between the projected pattern and thecaptured image.
 14. The method of claim 13 wherein the period of thepattern is equal to the window size.
 15. The method of claim 11 whereinthe projected pattern is a triangular pattern.
 16. The method of claim11 further comprising: modulating an intensity of light from the lightsource using a mask including transparent areas and opaque areas and alens to project the pattern onto the scene.
 17. The method of claim 11wherein the light source is a light emitting diode (LED).
 18. The methodof claim 11 wherein the computer model comprises a depth map.
 19. Themethod of claim 11 wherein the computer model comprises a video ratedepth map.
 20. The method of claim 11 wherein causing the camera tocapture the image of the scene including the projected pattern, causingthe camera to capture the image of the scene without the projectedpattern, and determining the difference are performed at a frame rateequal to a frame rate of the camera to generate depth maps at half theframe rate of the camera and to generate a video at half the frame rateof the camera, the video being free of the projected pattern.